Effective monitoring of deployed apps and services is crucial for DevOps teams, as it enables them to identify the causes of errors and performance problems. Comprehensive monitoring can be achieved with the right tools, such as Spacelift, Prometheus, Grafana, Elasticsearch, Logstash, Kibana, InfluxDB, New Relic, Kubecost, Splunk, Sensu, Datadog, Pagerduty, Dynatrace, Sysdig, Zabbix, Collectd, Perses, Netdata, Sentry, SolarWinds, Nagios, and AppDynamics. These tools cover various aspects of monitoring, including infrastructure monitoring, application performance monitoring (APM), log monitoring, network monitoring, security monitoring, user experience monitoring, end-to-end monitoring, container and orchestration monitoring, cost monitoring, and database monitoring.